Note work — quiet work, in police station (3,4)
I believe the answer is:
cop shop
'police station' is the definition.
(I've seen this before)
'note work quiet work' is the wordplay.
'note' becomes 'c' (musical note).
'work' becomes 'op' (abbreviation for opus).
'quiet' becomes 'sh'.
'work' becomes 'op' (abbreviation for opus**).
'c'+'op'+'sh'+'op'='COP SHOP'
'in' acts as a link.
(Other definitions for cop shop that I've seen before include "'Police station (3,4)'" , "Police station (slang)" , "office investigating crime" , "Nick" .)